The invention concerns the reconstruction of a section, such as a cross section, of an element of interest contained in an object, notably, in motion.
The invention has an especially important application in the medical field, in which reconstruction is undertaken of the internal structures of patients under examination and, in particular, the reconstruction of images of vessels of the heart.
The invention can, nevertheless, be applicable in other fields, notably, in industrial nondestructive control, in which examinations of the same type as medical examinations are performed.
In the medical field, a correct understanding of pathology, like, for example, the observation of stenosis in a coronary artery from X-ray images, is a particularly difficult task. In fact, the X-ray images are projected two-dimensional images. Consequently, interpretation of the images is particularly difficult.
The invention is aimed at providing a solution to this problem and proposes a method of reconstruction of a section, such as a cross section of an element of interest, like a portion of a vessel contained in an object, in which method several acquisitions of digital radiographic images of the element of interest are made, by using a moving camera rotating around the element of interest in a plane parallel to the plane of the section, for example, a plane perpendicular to the element of interest. A matching stage is carried out in which projected elements are located in all the acquired images, corresponding respectively to the projections of the element of interest in those acquired images.
The width of each projected element is determined and the section of the element of interest is reconstructed from the different widths determined.
The spatial orientation of the element of interest is advantageously determined from a prior reconstruction of a three-dimensional representation of the object, using, for example, an algebraic iterative algorithm of image reconstruction.
The principle of such an algebraic iterative algorithm of image reconstruction is well known to one skilled in the art and has already been the subject of considerable literature. One can mention, notably, the article by Gordon, Bender and Herman entitled xe2x80x9cAlgebraic reconstruction technique for tridimensional electron microscopy and X-ray photography,xe2x80x9d Journal of Theol. Biol. 29, pages 9471 to 781 (1970), or also French Patent Applications Nos. 89 03606 or 89 16906.
The method of reconstruction of a three-dimensional image of an object as described in French Patent Application No. 2,752,975 can also be used.
One skilled in the art may refer to these documents of the prior art for more information concerning the method of use of the image reconstruction algorithm and/or the phase of calibration of the camera.
When the object is in motion, for example, when the heart is involved, a technique of four-dimensional reconstruction of an image of an object in motion can also be advantageously used, as described in U.S. patent application Ser. No. 09/667,067 filed in the name of Vaillant et al. on Sep. 9, 2000, entitled xe2x80x9cProcess for Reconstructing a Tridimensional Image of an Objectxe2x80x9d, and assigned to assignee of the present application.